Means for automatically controlling the fuel injecting mechanism of internal combustion engines



CAMNER Jan. 20, 1942. H. ca. 2,270,410

MEANS FOR AUTOMATICALLY CONTROLLING THE FUEL INJECTING MECHANISM OFINTERNAL COMBUSTION ENGINES Flled Nov '7, 1959 an uncertain control.

Patented Jan. 20, 1942 UNITED STATES PATENT OFFICE MEANS FORAUTOMATICALLY CONTROL- LING THE FUEL INJECTING MECHANISM OF INTERNALCOMBUSTION ENGINES Hilding Gunnar Camner, Ektorp, Sweden, assignor toAktiebolaget Atlas Diesel, Stockholm,

Sweden Application November 7, 1939, Serial No. 303,222 In Sweden June1, 1938 4 Claims. (Cl. 123-140) In internal combustion engines it isdesired to automatically time the fuel injection at changes of thenumber of revolutions of the engine. Thus,

at a greater number of revolutions the fuel in- Jection should takeplace earlier than at a lower number of revolutions.

shaped curved members, are used, which involvesa complication. It alsooften occur'sthat it is desired to change the feed pressure of the fuel,which means that the above mentioned motion transmitting means has nolonger the desired action, but must be replaced by another meanssuitable for the changed pressure.

Devices have also been su gested, which are based on the utilization ofthe pressure changes.

in the suction pipe of the engine occuring at changes ofthe number ofrevolutions. However, such devices, which necessitate throttling of thesuction pipe, have the drawback that they must work at very lowpressures, which entails The present invention has forits object toavoid the above mentioned drawbacks and con sists essentially in that aservo-motor controlling the position of a member of the fuel injectingmechanism defining the time of injection is acted on by the-scavengingair.. The scavenging air is always at disposal and, since the pressureof same varies with the number of revolutions, the advantage is gainedthat the position of the injecting mechanism will be the desired one atany number of revolutions.

When running at a constant number of revolutions the scavengingpressure-varies with the torgue in such way that the said'pressureincreases at an increased torque and vice versa, j

substantially depending -'on the fact that the back-pressure in theexhaust conduit of the engine increases and decreases with the torque.

Thus, by making the time for the fuel injection dependent on thescavenging air the further advantage is gained that when running at acer- I tain constant number of revolutions the said I time will varywith the torque in such way that the injection occurs earlier at anincreased torque, whereby a better combustion is obtained and also agreater torque can be taken out. At lower torques and when idling theinjection occurs later and in this case no earlier ignition is requiredin order to eifect a complete combustion. The said later ignition bringsabout a more uniform and smooth. running of the engine, which is of agreat importance particularly in idling.

The annexed drawing illustrates diagrammatically an embodiment of adevice according to this invention. Fig.- 1 is a Side view showing theoutlines of an ordinary internal combustion engine having thecontrolling device applied thereto. scale of the controlling device. i

Fig. 2a is a fragmentary section showinga part of the controlling devicewith damping means incorporated therein. I

Referring to the drawing, M designates the engine proper and P anordinary scavenging air pump thereof driven by the engine in anyordinary convenient manner. The fuel pump mechaism, which also is ofknown type and need not be particularly described, is denoted by I andits cainshaft by 2, said shaft being driven by a drive shaft 3 drivenbythe engine in any ordinary manner. The cam-shaft 2 is provided withaxially disposed slots 4 and the drive shaft 3 with obliquely directedslots 5 meshing with correspondingly'arranged internal teeth in anaxially displaceable coupling-sleeve 6. Freely mounted in an annulargroove in said sleeve is a ring I provided with two diametricallyopposed gudgeons 8, to which a double-armed forked lever 9 is applied,saidlever being swingably mounted on a stationary pivot Ill. Thesaidpivot may, if desired, be replaced by an adjustable eccentric inorder tov change the relation of the arms of the forked lever 9. At itslower 'end the said lever is pivotally connected to the piston rod ll ofa servo-motor, comprising here a cylinder l2 and a piston I3 movabletherein. The cylinder chamber '14 at the one side of the pistoncommunicates through a pipe IS with the scavenging air receiver of theengine or any part of the scavenging air conduit, whereas the chamber l67 at the opposite side of the piston through a pipe l'l may be incommunication with the exhaustv conduit IQ of the engine at a placebetween the engine and a throttling member Illa in said conduit.Besides, the piston 1'3 is acted on by a Fig. 2 is a side view on anenlarged lows or the like.

spring l8 counter-acting the pressure in the cylinder chamber I.

When changing the number of revolutions of the engine or the torque,'thescavenging pressure takers-correspondingly, and the servo-motor-pistonl3 will be moved in theone direction or the other. By means of the lever9 the couplingsleeve 6 will thus be displaced in the one direction orthe other and simultaneously brought to rotate relatively to the driveshaft 3 on account of the obliquely directed slots 5 and thecorresponding intermeshing teeth. The said rotary motion is transmittedfrom the coupling-sleeve 6 to the cam-shaft 2 of the iniection pump l,whereby the time of the fuel injection will vary with the scavenging airpressure, 1. e. with the number of revolutions or the torque of theengine as above described.

the control. When throttling the exhaust gases,

the difference between the scavenging air pressure and the exhaust gaspressure will practically be unaltered, and thus the throttling will notaffect the control.

Evidently, the invention is not limited to any.

certain .type of fuel injecting mechanism, and the motion transmittingmeans between the servo-motor and the control member of the fuelinjecting mechanism can be of any desired kind.

This is true also of the servo-motor, which, for I instance, can beprovided with a membrane, bel- If desired, the piston of the servo-motoror the axially dispiaceable coupling- I sleeve may also be provided withsuitable dampingmeans in order-to prevent oscillations, particularlywhen idling or running at low loads. One such form'ofdamping means isillustrated in Fig. 2a by way of example, being of the general formdisclosed in my'co-pending application Ser. No. 303,221; In thisarrangement the servo-motor Piston l3 has a dash pot/piston 20 secureding air pump driven by t e engine,a fuel injecting' mechanism, means fordriving said mechanism from said engine including a member shiftable tovary the timing of fuel injection with respect to the cycle of operationof the engine, and means for automatically timing the fuel injection inaccordance with changes of the number of revolutions of the engine orthe torque, the lastmentioned means comprising a servomotor having amovable part acted on by the scavenging air and in operative connectionwith said member, said connection being arranged to cause the timing tobe advanced upon increase in said number of revolutions or torque, andvice-versa.

2. In an internal combustion engine, a scaven ing air pump driven bythe'engine, a fuel injecting mechanism? means for driving said mechanismfrom said engine including a member shiftable to vary the timing of fuelinjection with.

respect to the cycle of operation of the engine, and means forautomatically timing the fuel injection in accordance with changes ofthe number of revolutions of the engine or the torque, thelast-mentioned means comprising ,a servomotor having a movable partacted on by the scavenging air and also in opposition thereto by theexhaust gas pressure and in operative connection with said member, saidconnection being arranged to cause the timing to be advanced uponincrease in said number of revolutions or torque, and yice-ver a. r

3. In an ternal combustion engine, a scaven ing air pump driven by theengine, a fuel injecting mechanism, means for driving said mechanismfrom said engine including a member shiftable to vary the timing of fuelinjection with respect to the cycle of operation of the engine, meansfor automatically timing the fuel injection in accordance with changesof I the number of revolutions of the englneor the torque, the

last-mentioned means comprising a servo-motor" having a movable partacted on by the scavenging air and in operative connection with saidmember, and a damping device in connection with said movable part, saidconnection being arranged to cause the timing to be advanced uponincrease in said 'number of revolutions or torque, and vice-versa.

4. In an internal combustion engine, a scavenging air pump driven by theengine, a fuel injecting mechanism, means for driving said mechanismfrom said engine including a member shiftable to vary the timing of fuelinjection with respect to the cycle 0; operation of the engine, meansfor automatically timing the fuel injection in accordance with changesof the number 0 revolutions of the engine or the torque, thelastmentioned means comprising a servo-motor having a movable part actedon by the scavenging air and in operative connection with said member,said connection being arranged to cause the timing to be advanced uponincrease in said I

